I have an app where I present VC1 to pick a game and VC2 to submit plays for the selected game. When a user segues back from VC2 to VC1 I want to retain the game data for the game they were playing. Since it's iOS 6.0, I am using UIManagedDocument to access Core Data for storing and retrieving the game data. And I am totally stumped by the problem I am facing and after spending countless hours, I am reaching out to the wise folks on this forum.
When I run the code below in the Simulator, everything works fine, the data gets stored and I am also able to retrieve it and show it if the user picks the same game as earlier on to play. Unfortunately on the device, I can see that the data gets stored on segue - I put a breakpoint and looked at the persistentStore using iExplorer - but as soon as I go back to VC2 selecting the stored game, the persistentStore seems to be overwritten or purged of all data. In the debugger I noticed that the _persistentStores NSArray property of the _persistentStoreCoordinator object for "UIManagedDocument" always shows 0 when retrieval is done on the device.
Any help is much appreciated!!!
- (void) addOrGetDataToGamesDatabase:(CNPUIManagedDocument *)document withFlag:(BOOL)getFlag {
if (getFlag) {
NSLog(@"INSIDE addDataToGamesDatabase to get data");
}
else
NSLog(@"INSIDE addDataToGamesDatabase to set data");
dispatch_queue_t update = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH,0);
dispatch_sync(update, ^{
[document.managedObjectContext performBlockAndWait:^{
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Game"];
request.predicate = [NSPredicate predicateWithFormat:@"game = %@", self.selectedGameID];
NSError *error = nil;
NSLog(@"Persistent Store Name = %@", [[document class] persistentStoreName]);
NSArray *matches = [document.managedObjectContext executeFetchRequest:request error:&error];
NSLog(@"Fetch Error if any: %@ %@", error.debugDescription, [error userInfo]);
if (!matches || matches.count >1) {
NSLog(@"There is a problem with creating the game data");
}
//This is where it fails on the device as the match.count is always 0 as the fetch retrieves nothing
else if ([matches count] == 0) {
if (!getFlag) {
// Code to initialize the game data in store
}
}
else if ([matches count] == 1) {
// Another fetch - nested
if (!oTeammatches || [oTeammatches count] >1) {
NSLog(@"There is a problem with creating the offense team data");
}
else if ([oTeammatches count] == 0) {
if (!getFlag) {
//Code to initialize the team data in store
}
}
else if ([oTeammatches count] == 1) {
OTeam *newOTeam = [oTeammatches lastObject];
if (getFlag) {
//Retrieves data
//Shown by log lines beginning with "Getting"
}
else {
//Sets/Saves data
//Shown by log lines beginning with "Setting"
}
}
}
}];
if (!getFlag) {
[document updateChangeCount:UIDocumentChangeDone];
}
});
}
- (IBAction)pressBackButton:(UIButton *)sender {
[self addOrGetDataToGamesDatabase:self.gamesDatabase withFlag:NO];
if ((self.gamesDatabase.documentState & UIDocumentStateEditingDisabled) != UIDocumentStateEditingDisabled) {
[self.gamesDatabase saveToURL:self.gamesDatabase.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:^(BOOL success) {
if (success) {
NSLog(@"DB save file path: %@", self.gamesDatabase.fileURL);
NSLog(@"Saved!!!");
}
else
NSLog(@"Unable to save");
}];
}
[self performSegueWithIdentifier:@"BackToPickGame" sender:self];
}
- (void)viewDidLoad
{
[super viewDidLoad];
//Some Initialization code
if (!self.gamesDatabase) {
NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
url = [url URLByAppendingPathComponent:@"GameDB"];
self.gamesDatabase = [[CNPUIManagedDocument alloc] initWithFileURL:url];
NSLog(@"DB File URL generated: %@", url);
NSLog(@"self.gameDatabase initialized");
}
[self addOrGetDataToGamesDatabase:self.gamesDatabase withFlag:YES];
NSLog(@"Calling game with ID %@ , self.selectedGameID);
}
Some log info on the persistent store
DEVICE
First get on entering VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0x1fd28ce0>(
)
First set in VC2 on exiting VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0x1fd28ce0>(
(URL: file://localhost/var/mobile/Applications/4DD2D219-5AC1-406F-8020-260B01E46E0C/Documents/GameDB/StoreContent/persistentStore)
)
Second get on entering VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0x211d4660>(
)
SIMULATOR
First get on entering VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0x84e4b60>(
(URL: file://localhost/Users/Rujul/Library/Application%20Support/iPhone%20Simulator/6.0/Applications/B187169B-8D32-4BB1-AB41-33DB76637D9C/Documents/GameDB/StoreContent/persistentStore)
)
First set on exiting VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0x84e4b60>(
(URL: file://localhost/Users/Rujul/Library/Application%20Support/iPhone%20Simulator/6.0/Applications/B187169B-8D32-4BB1-AB41-33DB76637D9C/Documents/GameDB/StoreContent/persistentStore)
)
Second get on entering VC2
Printing description of document->_persistentStoreCoordinator:
Printing description of document->_persistentStoreCoordinator->persistentStores:
<_NSArrayM 0xf777910>(
(URL: file://localhost/Users/Rujul/Library/Application%20Support/iPhone%20Simulator/6.0/Applications/B187169B-8D32-4BB1-AB41-33DB76637D9C/Documents/GameDB/StoreContent/persistentStore)
)
